non_generative_constructor

The generative constructor '{0}' is expected, but a factory was found.

The analyzer produces this diagnostic when the initializer list of a constructor invokes a constructor from the superclass, and the invoked constructor is a factory constructor. Only a generative constructor can be invoked in the initializer list.

The following code produces this diagnostic because the invocation of the constructor super.one() is invoking a factory constructor:

class A {
  factory A.one() = B;
  A.two();
}

class B extends A {
  B() : super.one();
}

Change the super invocation to invoke a generative constructor:

class A {
  factory A.one() = B;
  A.two();
}

class B extends A {
  B() : super.two();
}

If the generative constructor is the unnamed constructor, and if there are no arguments being passed to it, then you can remove the super invocation.

Unless stated otherwise, the documentation on this site reflects Dart 3.7.3. Page last updated on 2025-05-08. View source or report an issue.